livermore



Jan. 31, 1928.

w. T. LIVERMORE BRAKE MECHANISM Filed June 2 ,1924

34 [NV EN TOR.

mLL MM 7.' A IVEKHORE.

A TTORNEYS.

Patented Jan. 3]., 1928.

Units stares Parent WILLIAM T. LIVEBM @1113. OF AL'LILH'IUVETN, PENNSYLVANIA, .thElElIGlllQIt T0 GRAHAIMI BROTHEREL 0F EVANEVILJZIE, INlJItANA,

ll. COHJPCPRATION.

BRAKE MECItL hNItdll L Another object ot the invent on incluees the idea of so proportiouir any type of braking surface that. the torce required to operate itwill be ot the proper amount and in the proper direction to lnroduce the desired result.

The full nature ot the invention will be understood from the acconnpanyinp; drawlugs and the following desert ion and claims.

In the drawings, Fig. 1 is a top plan view of a power shaft supporting a brake drum with which is associated a contracting trictional gripping drum-engaging; surtace in the form of shoes. Fig. 2 is a side elevational view thereof.

In the drawings 10 indicates a power shattcarrying a brake drum 11 suitably secured thereto and driven thereby. it. support '12 suitably supports a pair of identical brackets 13. These are suitably secured to the support; 12 by the base portion and have an outwardly projecting portion it. Another bracket 16 supports a pivotal bearing tOli11- ing bracket 17, which has a pair o't bearing ears 18 that pivotally support a link 19 by means of the pin 20 suitably secured by the cotter'pin. 21. This link 19 forms the floating support for the brake construction and the pivot described takes the force due to the friction of the brake. In the same plane as shown by the dotted center lines in Fig. 1 with this link, is another link 22, one end of which is connected to one arm 23 of a bell crank pivotally supported at 24: in a bracket 25. The other arm 26 of the bell crank is connected to a rod 2'7 by which force is applied to the brake construction. The link 22 also takes the force due to the triotion of the brake, as well as transmits the force applied through the rod 2? for braking purposes.

-Herein there is illustrated a brake druinengaging surface which is of the cont acting and shoe type. Each shoe is identical to the other, and, therefore, a description of one will suffice. Herein the shoe is shown proextension 3?.

vided with a curved surtace 28 adapted to support a brake lining 29 which adapted to engr "c the brake drum 11 and restrain the nmvenient ot the shaft: 10. ll

no; sorta ce at the shoe 28 is shown enat 30, and the end thereot terminates-z in a. plurality of stepped pivot bearings 31. Likewise, there is provided a pair of notches 32 which provide clearance for the head ot the rod or link 19, whereby said link sup ports a hinge or pivot pin The torecing arranpgement it will be noted, 's-ec 1. is secured by the particular formation ot the two identical shoes so that they C01llplelllfillttlly in forming a pivotally hinged construction provided rith a slot 32 tor the reception of the support.

The shoe in addition to the toregoi is.

provided with a plurality of reen'torcino; flan es or vanes, and herein the same are indicated by the numeral A trans *erse flange is indicated by the numeral 35 and another parallel thereto is indicated by the numeral 36. Said flange 36 extends upwardly at 37' and is provided with a hearing opening 38 suitably offset from the center of said extension. tine or more of the vanes 34: is provided with a toothed portion or lug 39. which tooth or lug is normally scatable on the bracket 14- when the brakes are released. Herr-in two oit said vanes are shown provided with said lugs. These lugs by cooperating with the bracket 14: provide a support for the weight of the two shoes when released. The lun's all) are also provided and the bracket 14; is adapt ed to adjustably support a pair of set screws 11 which limit the releasing movement of the shoes, by contacting the flanges as. A spring 15 between the shoe and adjacent bracket 14 assists in releasing the brake and maintaining the same released.

In one of the openings 38 oi the upper extension 37 on the shoe is supported a link 4-2, which link is adjustably supported therein by the nut 1-3. The other end of the link pivotally supported at 4E4 by a. link 4:53 that has one end pivot-ally supported at 4-6 to the other end ot the link 'lhe dist Qlllt't. between the centers 4st and is itu'licated by the dimension Z in lilo. l. The other end of the link h") is pivotaily supported. at 4.7 by a bolt alt; also adjustably receivable by the other opening; 38 in the other bracket The distance between the pin erein the drum-- Utl tltl

otal centers id and 47 is indicated by the dimension 0. Also see Fig. 2, the distance between the center line or plane of the linkand the plane of the support for the brake is indicated by the dimension (4 in Fig. 2. The distances 6 and c are calculated with reference to distance a, braking torque link tension and braking pressure to ob tain the result that the pressure between the brake drum and the left shoe is equal to the pressure between the brake drum and the right shoe.

Force applied to the end of link ill rocks bell crank 26-23 on pirot 24. Arcuate movement of arm 23 is carried linearly or tangentially thru link to lever 4:5. The pull on link 22 applies left hand shoe E28,

that is, moves the same into position but does not exert clamping force thereon. Up to this time continued pull on the link 2' is exerted to draw the right hand shoe into drum position. Both shoes thereupon are coaXi-ally arranged with respect to the drum and the remainder of the pull is applied to clamp the coaxially arranged shoes to the drum for braking. The floating anchorage permitssuch coaxial movement and also prevents rotation of the brakingsurface during the braking action. It will be apparent, therefore, by reason of the coaxial movement of the braking surface that the forces applied to each of the shoes are equal.

Pull on the end of each brake shoe multiplied by the distance from the plane of link 42 to pivot 33 is the moment equal to the friction moment of the shoe.

centrically with the drum as a result of the clamping action. 1

earner lVhile the invention has been described in great detail in the foregoing specific-a tions, the same is not to be limited thereby, for said description is considered to be il lustrative and not restrictive in character.

The invention claimed is:

1. In a brake construction, the combination of a drun'i-engagingr surface, a link connccted to one end of llLl drum-cu; guging surface, another link pivotally supported at the other end of said driunch ging: surface and pixxotall; sup 'iortiug d iii'st-mentioned link, a link conuccicd at one end to the second-inentioued lii for properly (lirecting the force applied thereto, and a bell crank connected to the other end of raid third-meritioned link for actuating the druntengrag'ing surface by applying through the third-1nentioned link a force of substantially correct amount to balance the frictional moment of the brake.

In a brake construction. a. rotatable drum, the combination with the ends of a surface for said drum, of a link brakii pirotz. 13' connected at one end to one of said surface ends, a linlc connected at one end to the other surface end, means for applying a clamping force to the free end of said second mentioned link, the first and second mentioned links pivotally connected to each other at a point between the connection of the second mentioned link with its braking surface and said clamping force, and a. floating support for said b'aking surface substantially intermediate the ends thereof.

3. In a brake construction, a rotatable drum, the combination with the ends oi a braking surface for said drum, of linl; mechanism connecting the ends of said bral ing surface, a pressure link operating to up ply braking pressure to said link meclmuism and a pivotal floating support for the intermediate portion of said braking surface and disposed in the same vertical plane with said pressure link. 7

In witness whereof, I have hereunto atfixed my signature.

WILLIAM T. LIVElRlil'GRE. 

